1. Field of the Invention
The present invention relates to a window frame comprising two frame members adapted to mutual locking engagement, between which members a window pane can be secured, one frame member comprising a tubular portion, into which a screw may be driven through the second frame member.
2. Description of the Related Art
Window frames of the type mentioned by way of introduction are known in which a window is retained between two frame members. These window frames are designed in such a manner that the two frame members constitute counterparts fitting into an aperture in a mounting surface such as a wall, a gate, a car body, etc., and to a certain extent, the frame members overlap the mounting surface. The two frame members are mounted from each side of the mounting surface, such that the members overlapping the mounting surface are arranged to clamp the surface, so that the window is secured in the mounting surface.
Such window frames may, for instance, be manufactured from a thermoplastic material by injection moulding or the like.
To obtain a locking engagement between the two frame members, one of the frame members may be provided with one or more tubular portions, whereas the second frame member may be provided with holes at places corresponding to the positioning of the tubular parts on the first-mentioned frame member.
By driving a screw through the holes and into the frame, the two frame members may be brought into locking engagement. The screw thus engages the tubular portion and pulls the two frame members together. During assembly, the screw cuts a thread which ensures a locking engagement.
Typically, when such frames are to be mounted, one out of three mounting situations presents itself. Namely, the primary mounting in a factory, the secondary mounting by a fitter at the place of installation or the tertiary mounting by the end user.
The primary mounting situation may, for instance, be mounting of a frame in a garage door in a factory. Mounting in a factory typically involves a large number of items, and the mounting process will as a consequence be automated.
The secondary mounting situation may be mounting of frames with window panes at the place of installation. This might, for instance, include postmounting of windows in an already existing, previously installed garage door, which has not previously been provided with windows. In such instances, a fitter has to cut openings first, or there may be a need to change to other types of windows and frames.
The tertiary mounting situation is the one made by the end user. In this case it may for instance be a question of replacing a single defective pane, in an already existing, previously mounted garage door. In such a case, the end user needs to be, able to dismount the frame without ruining it, insert a new pane and then remount the frame.
It is important that the mounting in the tertiary situation takes place without the use of special tools, because the typical end user is assumed to not possess special tools. Moreover, the end user cannot be assumed to possess any essential experience in, or knowledge of, dismounting (or mounting) window frames. It is important that the end user can intuitively dismount the window frames, such that, when trying to separate the frame members, the end user does not inadvertently ruin them.
The previously mentioned screw mounting step does meet the requirements of the secondary and tertiary mounting situations. The only tool required being a suitable screwdriver for screwing the screws in and out.
The requirement to install screws does, however, conflict with the primary mounting situation, where there is a need for the quickest possible mounting of the comparatively large number of screws necessary for holding the frame together. Screwing in of the screws one by one is, even when a robot is used, fairly time-consuming, and by simultaneous screwing in of several or all screws with several tools, the complexity of the required equipment increases, and erection or readjustment time therefore becomes time-consuming.
With a view to automatic, mounting, frames have admittedly already been developed, in which screwing is completely avoided, as self-locking members are pressed into one another. However, these frames do not meet the requirements of the second and tertiary mounting, due to the fact that either the frames cannot be disassembled without the frame members being ruined, or a separation can only be made by use of a special tool or by someone having a special knowledge of the construction of the locking mechanism.